Sodium in food is an inorganic salt, mainly found in table salt and most foods, is the main source of sodium in the human body, plays an important role in the human body, can regulate body water, synergistic muscle movement, auxiliary nerve information transmission. 1, regulation of body water: inside and outside the cell on both sides of the distribution of a large number of sodium and potassium ions, any side of the water too much or too little, through the cell membrane to regulate the direction of water movement. This mechanism is also known as “sodium-potassium pump”; 2, synergistic muscle movement: sodium and potassium ions in and out of the cell will generate electrical signals, prompting muscle contraction and diastole, in the heart and other visceral activity is also the same role; 3, auxiliary nerve information transmission: through the process of sodium and potassium ions in and out of the cell, so that nerve information 3, auxiliary nerve information transmission: through the process of sodium and potassium ions in and out of the cell, so that nerve information is transmitted to the whole body, also relies on “sodium-potassium pump” to achieve. The lack of sodium in the body may lead to nerve conduction disorders. In addition, it is important to avoid a high-salt diet for a long time to prevent the body from sodium-potassium imbalance, resulting in thirst, swelling and other symptoms, as well as avoiding serious diseases such as hypertension, stroke and renal insufficiency.